1. Field of the Invention
The present invention relates generally to electric cooking appliances and, more particularly, to an electric cooking or food warming appliance having a thin food contacting surface, preferably of stainless steel, that intimately engages a thicker heat conductive core or heat sink plate of copper or aluminum by means of a vacuum to maximize heating uniformity and minimize heat loss.
2. Description of Related Art
Briefly stated, the invention disclosed in parent application Ser. No. 11/245,478 is directed to a composite griddle plate comprising a core consisting of a metal plate having a high coefficient of thermal conductivity such as copper or aluminum. The core plate is faced at least with an upper sheet of a metal such as stainless steel or titanium which defines the cook surface of the griddle plate. The interface between the core plate and upper sheet is under the reduced pressure of a vacuum so as to cause intimate contact between the core and cook surface which increases the thermal conductivity to the cook surface and, thus, reduces the thermal recovery time of the griddle.
Various additional embodiments of the original invention are also disclosed in the parent application. For example, the griddle plate of one such embodiment comprises a high heat conductivity core of copper or aluminum having upper and lower sheets of stainless steel in intimate contact with the core. The entire perimeter of the griddle plate is sealed as by welding and the interior is under a permanently sealed vacuum. Another such embodiment utilizes an upper sheet of stainless steel or other metal having a non-stick coating applied thereto. The upper sheet is removably secured to the heat conductive core plate under vacuum utilizing a high temperature gasket or adhesive sealant to maintain the vacuum. The upper sheet may be mechanically secured by bolts or the construction may be placed under a constant vacuum using a vacuum pump. When the non-stick surface ages and/or otherwise loses its non-stick properties, such as with a PTFE-type non-stick coating, the upper sheet can be easily replaced with a freshly non-stick coated upper sheet and the vacuum reestablished.